Safely check for suspend function parent

The issue here is that the function can be in unlowered file, and
thus its parent package fragment and not class.

 #KT-49317 Fixed

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java

@@ -10179,6 +10179,12 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/coroutines/kt49168.kt");
         }
 
+        @Test
+        @TestMetadata("kt49317.kt")
+        public void testKt49317() throws Exception {
+            runTest("compiler/testData/codegen/box/coroutines/kt49317.kt");
+        }
+
         @Test
         @TestMetadata("kt49645.kt")
         public void testKt49645() throws Exception {